Network Working Group E. York, Ed.
Internet-Draft C. Daboo, Ed.
Intended status: Standards Track Apple Inc.
Expires: July 10, 2015 M. Douglass, Ed.
RPI
January 6, 2015
VPOLL: Consensus Scheduling Component for iCalendardraft-york-vpoll-03
Abstract
This specification introduces a new iCalendar component which allows
for consensus scheduling, that is, voting on a number of meeting or
task alternatives.
Status of This Memo
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This Internet-Draft will expire on July 10, 2015.
Copyright Notice
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document authors. All rights reserved.
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information or availability as this may reveal something of the
organizations internal activities.
A number of studies have shown that large amounts of time are spent
trying to come to an agreement - up to and beyond 20 working hours
per meeting. Many organizers fall back on other approaches such as
phone calls and email to determine a suitable time.
Online services have appeared as a result and these allow
participants to vote on a number of alternatives without revealing or
using freebusy or availability. When agreement is reached a
conventional scheduling message may be sent to the attendees. This
approach appears to reach consensus fairly rapidly. Peer pressure
may have some bearing on this as all voters are usually able to see
the current state of the voting and may adjust their own meeting
schedules to make themselves available for a popular choice.
The components and properties defined in this specification provide a
standardized structure for this process and allow calendar clients
and servers and web based services to interact.
These structures also have uses beyond the relatively simple needs of
most meeting organizers. The process of coming to consensus can also
be viewed as a bidding process.
2. Conventions and Terms Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
Additionally this document uses the following terms:
Consensus Scheduling: The process whereby parties come to some
agreement on meeting or task alternatives and then book that
meeting or task.
Active VPOLL: A VPOLL may have a DTSTART, DTEND and DURATION which
may define the start and end of the active voting period.
Voter: A participant who votes on the alternatives. A voter need
not be an attendee of any of the alternatives presented.
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This specification defines components and properties which can be
used for simple consensus scheduling but also have the generality to
handle more complex cases. To provide an easy (and for many -
sufficient) introduction to consensus scheduling and VPOLL we will
outline the flow of information for the simple case of voting on a
number of meeting alternatives which differ only in time. In
addition the voters will all be potential attendees.
This specification not only defines data structures but adds a new
iTIP method used to broadcast teh status of the poll. This document
will show how a VPOLL object is used to inform voters of the state of
a simple vote on some alternatives.
3.1. The VPOLL Component: An Overview
The VPOLL component acts as a wrapper for a number of alternatives to
be voted on, together with some properties and a new component used
to maintain the state of the voting. For our simple example the
following VPOLL properties and sub-components are either required or
appropriate:
DTSTAMP: The usual [RFC5545] property.
SEQUENCE: The usual [RFC5545] property. See below for SEQUENCE
behavior.
UID: The usual [RFC5545] property.
ORGANIZER: The usual [RFC5545] property. In general this need not
be an organizer of any of the alternatives. In this simple
outline we assume it is the same.
SUMMARY: The usual [RFC5545] property. This optional but
recommended property provides a short title to the poll.
DESCRIPTION: The usual [RFC5545] property. This optional property
provides more details.
DTEND: The usual [RFC5545] property. This optional property
provides a poll closing time and date after which the VPOLL is no
longer active.
POLL-MODE: A new property which defines how the votes are used to
obtain a result. For our use case it will take the value "BASIC"
meaning one event will be chosen from the alternatives.
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POLL-COMPLETION: A new property which defines who (server or client)
chooses and/or submits the winning choice. In our example the
value is "SERVER-SUBMIT" which means the client chooses the winner
but the server will submit the winning choice.
POLL-PROPERTIES: A new property which defines which iCalendar
properties are being voted on. For our use case it will take the
value "DTSTART, LOCATION" meaning only those properties are
significant for voting. Other properties in the events may differ
but are not considered significant for the voting process.
VVOTER: A new component. There is one of these for each voter and
it contains a VOTER property to identify the voter and one VOTE
component for each item being voted on.
VOTE: A new component. There is one of these for each voter choice.
It usually contains at least a POLL-ITEM-ID property to identify
the choice and a RESPONSE property to provide a vote. For more
complex poll modes it may contain other information such as cost
or estimated duration.
VOTER: A new property. There is one of these for each voter and it
is similar to the [RFC5545] ATTENDEE property. It identifies the
VVOTER component to show who is taking part in the voting and
their results.
VEVENT: In our simple use case there will be multiple VEVENT sub-
components defining the alternatives. Each will have a different
date and or time for the meeting.
Putting that together we can construct an example VPOLL with 3 voters
and 3 alternative meetings:
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BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example//Example
METHOD:REQUEST
BEGIN:VPOLL
POLL-MODE:BASIC
POLL-COMPLETION:SERVER-SUBMIT
POLL-PROPERTIES:DTSTART,LOCATION
ORGANIZER:mailto:mike@example.com
UID:sched01-1234567890
DTSTAMP:20120101T000000Z
SUMMARY:What to do this week
DTEND:20120101T000000Z
BEGIN: VVOTER
VOTER:mailto:cyrus@example.com
END VVOTER
BEGIN: VVOTER
VOTER:mailto:eric@example.com
END VVOTER
BEGIN: VVOTER
VOTER:mailto:mike@example.com
END VVOTER
BEGIN:VEVENT.......(with a poll-item-id=1)
END:VEVENT
BEGIN:VEVENT.......(with a poll-item-id=2)
END:VEVENT
BEGIN:VEVENT.......(with a poll-item-id=3)
END:VEVENT
END:VPOLL
END:VCALENDAR
As can be seen in the example above, there is an iTIP METHOD property
with the value REQUEST. The VPOLL object will be distributed to all
the voters, either through iMIP or through some VPOLL enabled
service.
3.2. The VPOLL Candidate Subcomponents
Within the VPOLL component we have the alternatives to vote on.
These are standard [RFC5545] components. For our simple use case
they are all VEVENT components. In addition to the usual [RFC5545]
properties the POLL-ITEM-ID property is used for a VPOLL to identify
the choice.
POLL-ITEM-ID: This provides a unique reference to the sub-component
within the VPOLL. It's value SHOULD be a small integer.
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Upon receipt of a VPOLL REQUEST the voter will reply with a VPOLL
component containing their vote. In our simple case it will have the
following properties and components:
DTSTAMP: The usual [RFC5545] property.
SEQUENCE: The usual [RFC5545] property. See below for SEQUENCE
behavior.
UID: Same as the request.
ORGANIZER: Same as the request.
SUMMARY: Same as the request.
VVOTER: One only.
VOTER: One only inside the VVOTER component - the voter replying.
VOTE: One per item being voted on inside the VVOTER component.
There does not need to be one for each choice.
POLL-ITEM-ID: One inside each VOTE component to identify the choice.
RESPONSE: One inside each VOTE component to specify the vote.
Note that a voter can send a number of REPLYs for each REQUEST sent
by the organizer. Each REPLY completely replaces the voting record
for that voter for all components being voted on. In our example, if
Eric responds and votes for items 1 and 2 and then responds again
with a vote for only item 3, the final outcome is one vote on item 3.
Putting this together we can construct an example REPLY VPOLL from
Cyrus:
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BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example//Example
METHOD: REPLY
BEGIN:VPOLL
ORGANIZER:mailto:mike@example.com
UID:sched01-1234567890
DTSTAMP:20120101T010000Z
SUMMARY:What to do this week
BEGIN:VVOTER
VOTER:mailto:cyrus@example.com
BEGIN:VOTE
POLL-ITEM-ID:1
RESPONSE:50
COMMENT:Work on iTIP
END:VOTE
BEGIN:VOTE
POLL-ITEM-ID:2
RESPONSE:100
COMMENT:Work on WebDAV
END:VOTE
BEGIN:VOTE
POLL-ITEM-ID:3
RESPONSE:0
END:VOTE
END:VVOTER
END:VPOLL
END:VCALENDAR
3.4. VPOLL updates
When the organizer receives a response from one or more voters the
current state of the poll is sent to all voters. The new iTIP method
POLLSTATUS is used. The VPOLL can contain a reduced set of
properties but MUST contain DTSTAMP, SEQUENCE (if not 0), UID,
ORGANIZER and one or more VVOTER components each populated with a
VOTER property and zero or more VOTE components.
An example:
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After a number of REPLY messages have been received the poll will be
considered complete. If there is a DTEND on the poll the system may
automatically close the poll, or the organizer may, at any time,
consider the poll complete. A VPOLL can be completed (and
effectively closed for voting) by sending an iTIP REQUEST message
with the VPOLL STATUS property set to COMPLETED.
The poll winner is confirmed by sending a final iTIP REQUEST message
with the VPOLL STATUS property set to CONFIRMED. In this case the
VPOLL component contains all the events being voted on along with a
POLL-WINNER property to identify the winning event.
The VPOLL confirmation example:
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example//Example
METHOD: REQUEST
BEGIN:VPOLL
ORGANIZER:mailto:douglm@example.com
UID:sched01-1234567890
DTSTAMP:20120101T030000Z
COMPLETED:20120101T030000Z
POLL-COMPLETION:SERVER-SUBMIT
SEQUENCE:0
SUMMARY:What to do this week
STATUS:CONFIRMED
POLL-WINNER:3
BEGIN:VEVENT.......(with a poll-item-id=1)
END:VEVENT
BEGIN:VEVENT.......(with a poll-item-id=2)
END:VEVENT
BEGIN:VEVENT.......(with a poll-item-id=3)
END:VEVENT
END:VPOLL
END:VCALENDAR
Note that as the POLL-COMPLETION property is set to SERVER-SUBMIT the
server will submit the winning choice and when it has done so set the
STATUS to "SUBMITTED".
3.6. Other Responses
A voter being asked to choose between a number of ORGANIZER supplied
alternatives may find none of them acceptable or may simply not care.
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An alternative response, which may be disallowed, is to send back the
respondees availability or freebusy or even one or more new,
alternative choices.
This is accomplished by responding with a VOTE component which has no
POLL-ITEM-ID property. In this case it MUST contain some alternative
information. What form this takes depends on the poll mode in
effect.
4. iCalendar Extensions4.1. Updated Relation Type Value
Relationship parameter type values are defined in section 3.2.15. of
[RFC5545]. This specification updates that type to include the new
relationship value POLL to provide a link to the VPOLL component in
which the current component appears.
Format Definition:
This property parameter is redefined by the following notation:
reltypeparam /= "RELTYPE" "=" "POLL"
; Property value is a VPOLL uid
Description: This parameter can be specified on a property that
references another related calendar component. The new parameter
value indicates that the associated property references a VPOLL
component which contains the current component.
4.2. Updated Status Value
Status property values are defined in section 3.8.1.11. of [RFC5545].
This specification updates that type to define valid VPOLL status
values.
Format Definition:
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This property parameter is redefined by the following notation:
statvalue /= statvalue-poll
; Status values for "VPOLL".
statvalue-poll = "IN-PROCESS"
/ "COMPLETED" ; Poll has closed,
; nothing has been chosen yet
/ "CONFIRMED" ; Poll has closed and
; winning items confirmed
/ "SUBMITTED" ; The winning item has been
; submitted
/ "CANCELLED"
Description: These values allow clients and servers to handle the
choosing and submission of winning choices.
If the client is choosing and the server submitting then the
client should set the POLL-WINNER property, set the status to
CONFIRMED and save the poll. When the server submits the winning
choice it will set the status to SUBMITTED.
4.3. New Property Parameters4.3.1. Required
Parameter name: REQUIRED
Purpose: To specify whether the associated property is required in
the current context.
Format Definition:
This parameter is defined by the following notation:
requirededparam = "REQUIRED" "=" ("TRUE" / "FALSE")
; Default is FALSE
Description: This parameter MAY be specified on REPLY-URL and, if
the value is TRUE, indicates the organizer requires all replies to
be made via the specified service rather than iTIP replies.
4.3.2. Stay-Informed
Parameter name: STAY-INFORMED
Purpose: To specify the voter also wants to be added as an ATTENDEE
when the poll is confirmed.
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Format Definition:
This parameter is defined by the following notation:
stayinformedparam = "STAY-INFORMED" "=" ("TRUE" / "FALSE")
; Default is FALSE
Description: This parameter MAY be specified on VOTER and, if the
value is TRUE, indicates the voter wishes to be added to the final
choice as a non participant.
4.4. New Properties4.4.1. Accept-Response
Property name: ACCEPT-RESPONSE
Purpose: This property is used in VPOLL to indicate the types of
component that may be supplied in a response.
Property Parameters: Non-standard or iana parameters can be
specified on this property.
Conformance: This property MAY be specified in a VPOLL component.
Description: When used in a VPOLL this property indicates what
allowable component types may be returned in a reply. Typically
this would allow a voter to respond with their freebusy or
availability rather than choosing one of the presented
alternatives
If this property is not present voters are only allowed to respond
to the choices in the request.
Format Definition:
This property is defined by the following notation:
acceptresponse = "ACCEPT-RESPONSE" acceptresponseparams ":"
iana-token ("," iana-token) CRLF
acceptresponseparams = *(";" other-param)
4.4.2. Poll-Completion
Property name: POLL-COMPLETION
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Purpose: This property is used in VPOLL to indicate whether the
client or server is responsible for choosing and/or submitting the
winner(s).
Description: When a VPOLL is stored on a server which is capable of
handling choosing and submission of winning choices a value of
SERVER indicates that the server should close the poll, choose the
winner and submit whenever it is appropriate to do so.
For example, in BASIC poll-mode, reaching the DTEND of the poll
could trigger this server side action.
Server initiated submission requires that the submitted choice
MUST be a valid calendaring component.
POLL-COMPLETION=SERVER-SUBMIT allows the client to set the poll-
winner, set the status to CONFIRMED and then store the poll on the
server. The server will then submit the winning choice and set
the status to SUBMITTED.
Format Definition:
This property is defined by the following notation:
poll-completion = "POLL-COMPLETION" pcparam ":" pcvalue CRLF
pcparam = *(";" other-param)
pcvalue = "SERVER" ; The server is responsible for both choosing and
; submitting the winner(s)
/ "SERVER-SUBMIT" ; The server is responsible for
; submitting the winner(s). The client chooses.
/ "SERVER-CHOICE" ; The server is responsible for
; choosing the winner(s). The client will submit.
/ "CLIENT" ; The client is responsible for both choosing and
; submitting the winner(s)
/ iana-token
/ x-name
;Default is CLIENT
Example:
The following is an example of this property:
POLL-COMPLETION: SERVER-SUBMIT
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Property name: POLL-ITEM-ID
Purpose: This property is used in VPOLL child components as an
identifier.
Value type: INTEGER
Property Parameters: Non-standard parameters can be specified on
this property.
Conformance: This property MUST be specified in a VOTE component and
in VPOLL choice items.
Description: In a METHOD:REQUEST each choice component MUST have a
POLL-ITEM-ID property. Each set of components with the same POLL-
ITEM-ID value represents one overall set of items to be voted on.
POLL-ITEM-ID SHOULD be a unique small integer for each component
or set of components. If it remains the same between REQUESTs
then the previous response for that component MAY be re-used. To
force a re-vote on a component due to a significant change, the
POLL-ITEM-ID MUST change.
Format Definition:
This property is defined by the following notation:
pollitemid = "POLL-ITEM-ID" pollitemdparams ":"
integer CRLF
pollitemidparams = *(
(";" other-param)
)
4.4.4. Poll-Mode
Property name: POLL-MODE
Purpose: This property is used in VPOLL to indicate what voting mode
is to be applied.
Property Parameters: Non-standard or iana parameters can be
specified on this property.
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Conformance: This property MAY be specified in a VPOLL component.
If not specified it defaults to BASIC.
Description: The poll mode defines how the votes are applied to
obtain a result. BASIC mode, the default, means that the voters
are selecting one component (or group of components) with a given
POLL=ITEM-ID.
Other polling modes may be defined in updates to this
specification. These may allow for such modes as ranking or task
assignment.
Format Definition: or its sub-components
This property is defined by the following notation:
pollmode = "POLL-MODE" pollmodeparams ":"
("BASIC" / iana-token / other-token) CRLF
pollmodeparams = *(";" other-param)
4.4.5. Poll-properties
Property name: POLL-PROPERTIES
Purpose: This property is used in VPOLL to define which icalendar
properties are being voted on.
Property Parameters: Non-standard or iana parameters can be
specified on this property.
Conformance: This property MAY be specified in a VPOLL component.
Description: This property defines which icalendar properties are
significant in the voting process. It may not be clear to voters
which properties are varying in a significant manner. Clients may
use this property to highlight those listed properties.
Format Definition:
This property is defined by the following notation:
pollproperties = "POLL-PROPERTIES" pollpropparams ":"
text *("," text) CRLF
pollpropparams = *(";" other-param)
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Property name: POLL-WINNER
Purpose: This property is used in a basic mode VPOLL to indicate
which of the VPOLL sub-components won.
Value type: INTEGER
Property Parameters: Non-standard parameters can be specified on
this property.
Conformance: This property MAY be specified in a VPOLL component.
Description: For poll confirmation each child component MUST have a
POLL-ITEM-ID property. For basic mode the VPOLL component SHOULD
have a POLL-WINNER property which MUST correspond to one of the
POLL-ITEM-ID properties and indicates which sub-component was the
winner.
Format Definition:
This property is defined by the following notation:
pollwinner = "POLL-WINNER" pollwinnerparams ":"
integer CRLF
pollwinnerparams = *(";" other-param)
; Used with a STATUS:CONFIRMED VPOLL to indicate which
; components have been confirmed
4.4.7. Reply-URL
Property name: REPLY-URL
Purpose: This property may be used in scheduling messages to
indicate additional reply methods, for example a web-service.
Property Parameters: Non-standard, required or iana parameters can
be specified on this property.
Conformance: This property MAY be specified in a VPOLL component.
Description: When used in a scheduling message this property
indicates additional or required services that can be used to
reply. Typically this would be a web service of some form.
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Format Definition:
This property is defined by the following notation:
reply-url = "REPLY-URL" reply-urlparams ":" uri CRLF
reply-urlparams = *(
(";" requiredparam) /
(";" other-param)
)
4.4.8. Response
Property name: RESPONSE
Purpose: To specify a response vote.
Value type: INTEGER
Format Definition:
This property is defined by the following notation:
response = "RESPONSE" response-params ":" integer CRLF
; integer value 0..100
responseparams = *(";" other-param)
Description: This property is used in VOTE components to provide the
value of the voters response. This property allows for fine
grained responses which are appropriate to some applications. For
the case of individuals voting for a choice of events, client
applications SHOULD conform to the following convention for the
value:
* 0 - 39 A "NO vote".
* 40 - 79 A "MAYBE" vote
* 80 - 89 A "YES - but not preferred vote"
* 90-100 A "YES" vote.
Clients MUST preserve the response value when there is no change
from the user even if they have a UI with fixed states (e.g.
yes/no/maybe).
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Property name: VOTER
Purpose: This property is used in VVOTER components to indicate
recipients of the poll and to identify that component as
containing the voters responses.
Value type: The value type for this property is cal-address.
Property Parameters: Non-standard, cutype, member, role, rsvp,
delto, delfrom, sentby, cn, dir, lang or stayinformed parameters
can be specified on this property.
Conformance: This property MAY be specified in a VPOLL component or
its sub-components.
Description: This property appears in the VVOTER component only and
indicates a recipient of the poll and their responses.
Format Definition:
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This property is defined by the following notation:
voter = "VOTER" voterparams ":" cal-address CRLF
voterparam = *(
;
; The following are OPTIONAL,
; but MUST NOT occur more than once.
;
(";" cutypeparam) / (";" memberparam) /
(";" roleparam) /
(";" rsvpparam) / (";" deltoparam) /
(";" delfromparam) / (";" sentbyparam) /
(";" cnparam) / (";" dirparam) /
(";" languageparam) /
(";" stayinformedparam) /
;
; The following are OPTIONAL, but MUST NOT occur
; more than once. They are defined in RFC6638
;
(";" scheduleagentparam) /
(";" scheduleforcesendparam) /
(";" schedulestatusparam) /
;
; The following is OPTIONAL,
; and MAY occur more than once.
;
(";" other-param)
;
)
Note 1 RSVP=TRUE MAY be used by the organizer to force the voter to
reset their state and re-vote.
Note 2 scheduleagentparam, scheduleforcesendparam and
schedulestatusparam are all related to CalDAV scheduling and are
defined in [RFC6638]. Their semantics are exactly as defined in
that specification.
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Description: This component provides a mechanism by which voters can
vote on provided choices. The outcome depends upon the POLL-MODE
in effect.
The VVOTER components in VPOLL requests provide information on
each recipient who will be voting - both their identity through
the VOTER property and their votes through the VOTE components.
If specified, the "DTSTART" property defines the start or opening
of the poll active period. If absent the poll is presumed to have
started when created.
If "DTSTART" is present "DURATION" MAY be specified and indicates
the duration, and hence the ending, of the poll. The value of the
property MUST be a positive duration.
"DTEND" MAY be specified with or without "DTSTART" and indicates
the ending of the poll. If DTEND is specified it MUST be later
than the DTSTART or CREATED property.
If one or more VALARM components are included in the VPOLL they
are not components to be voted on and MUST NOT contain a POLL-
ITEM-ID property. VALARM sub-components may be used to provide
warnings to the user when polls are due to start or end.
Need some text to describe what relative alarms are relative to.
4.5.2. VVOTER Component
Component name: VPOLL
Purpose: This component contains identification of the recipient and
voter and their responses.
Format Definition:
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This property is defined by the following notation:
voterc = "BEGIN" ":" "VVOTER" CRLF
voterprop
*votec *iana-comp *x-comp
"END" ":" "VVOTER" CRLF
voterprop = *(
;
; The following are REQUIRED,
; but MUST NOT occur more than once.
;
dtstamp / voter /
;
; The following are OPTIONAL,
; but MUST NOT occur more than once.
;
created / description / last-mod / seq /
status / summary / url /
;
; The following are OPTIONAL,
; and MAY occur more than once.
;
attach / categories / comment /
contact / rstatus / related /
resources / x-prop / iana-prop
;
)
Description: This component contains a VOTER property identifying a
recipient and voter and zero or more VOTE components containing
their responses.
The VOTER property in VVOTER objects refers to a recipient who
will be voting - RSVP=TRUE is used by the organizer to force the
voter to reset their state and re-vote
4.5.3. VOTE Component
Component name: VPOLL
Purpose: This component contains the vote for a single choice.
Format Definition:
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This component is defined by the following notation:
votec = "BEGIN" ":" "VOTE" CRLF
voteprop
*eventc *todoc *journalc *freebusyc
*availabilityc *alarmc *iana-comp *x-comp
"END" ":" "VOTE" CRLF
voteprop = *(
;
; The following are OPTIONAL,
; but MUST NOT occur more than once.
;
pollitemid / response /
;
; The following are OPTIONAL,
; and MAY occur more than once.
;
comment / x-prop / iana-prop
;
)
Description: This component contains the voters response for a
single choice.
The required and optional properties and their meanings depend
upon the POLL-MODE in effect.
For any POLL-MODE, POLL-ITEM-ID is used to associate the
information to a choice supplied by the organizer.
If allowed by the POLL-MODE a VOTE component without a POLL-ITEM-
ID may be provided in a REPLY to indicate a possible new choice or
to provide information to the ORGANIZER - such as the respondees
availability.
5. Poll Modes
The VPOLL component is intended to allow for various forms of
polling. The particular form in efffect is indicated by the POLL-
MODE property.
New poll modes can be registered by including a completed POLL-MODE
Registration Template (see Section 9.3) in a published RFC.
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BASIC poll mode is the form of voting in which one possible outcome
is chosen from a set of possibilities. Usually this will be
represented as a number of possible event or task objects one of
which will be selected.
5.1.1. Property restrictions
This poll mode has the following property requirements:
POLL-ITEM-ID: Each contained sub-component or group of sib-
components that is being voted upon MUST contain a POLL-ITEM_ID
property which is unique within the context of the POLL. The
value MUST NOT be reused when events are removed and/or added to
the poll.
POLL-WINNER: On confirmation of the poll this property MUST be
present and identifies the winning component or set of components.
5.1.2. Outcome reporting
To confirm the winner the POLL-WINNER property MUST be present and
the STATUS MUST be set to CONFIRMED.
When the winning VEVENT or VTODO is not a scheduled entity, that is,
it has no ORGANIZER or ATTENDEES it MUST be assigned an ORGANIZER
property and a list of non-participating ATTENDEEs. This allows the
winning entity to be distributed to the participants through iTIP or
some other protocol.
6. iTIP Extensions
This specification introduces a number of extensions to [RFC5546].
In group scheduling the parties involved are organizer and attendees.
In VPOLL the parties are organizer and voters.
For many of the iTIP processing rules the voters take the place of
attendees.
6.1. Methods
There are some extensions to the behavior of iTIP methods for a VPOLL
object and one new method is defined.
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+----------------+--------------------------------------------------+
| Method | Description |
+----------------+--------------------------------------------------+
| PUBLISH | No changes (yet) |
| | |
| REQUEST | Each child component MUST have a POLL-ITEM-ID |
| | property. Each set of components with the same |
| | POLL-ITEM-ID value represents one overall set of |
| | items to be voted on. |
| | |
| REPLY | There MUST be a single VPOLL component which |
| | MUST contain a single VVOTER component. That |
| | VVOTER component MUST contain a single VOTER |
| | property identifying the voter and 0 or more |
| | VOTE components. A VOTE component contains |
| | either a single POLL-ITEM-ID and a single |
| | RESPONSE property providing the vote for a |
| | particular item or a VFREEBUSY or VAVAILABILITY |
| | child component showing overall busy/available |
| | time. |
| | |
| ADD | Not supported for VPOLL. |
| | |
| CANCEL | There MUST be a single VPOLL component with UID |
| | matching that of the poll being cancelled. |
| | |
| REFRESH | The organizer returns a METHOD:REQUEST with the |
| | current full state, or a METHOD:CANCEL or an |
| | error if no matching poll is found. |
| | |
| COUNTER | Not supported for VPOLL. |
| | |
| DECLINECOUNTER | Not supported for VPOLL. |
| | |
| POLLSTATUS | Used to send the current state of the poll to |
| | all voters. The VPOLL can contain a reduced set |
| | of properties but MUST contain DTSTAMP, SEQUENCE |
| | (if not 0), UID, ORGANIZER properties and VVOTER |
| | components. |
| | |
+----------------+--------------------------------------------------+
The following table shows the above methods broken down by who can
send them with VPOLL components.
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+-------------+-------------------------------------------------+
| Originator | Methods |
+-------------+-------------------------------------------------+
| Organizer | CANCEL, PUBLISH, REQUEST, POLLSTATUS |
| | |
| Voter | REPLY, REFRESH, REQUEST (only when delegating) |
+-------------+-------------------------------------------------+
6.2. Interoperability Models
Most of the standard iTIP specification applies with respect to
organizer and voters.
6.2.1. Delegation
TBD
6.2.2. Acting on Behalf of Other Calendar Users
TBD
6.2.3. Component Revisions
Need to talk about what a change in SEQUENCE means
Sequence change forces a revote.
New voter - no sequence change
Add another poll set or change poll item ids or any change to a child
component - bump sequence
6.2.4. Message Sequencing
TBD
6.3. Application Protocol Elements6.3.1. Methods for VPOLL Calendar Components
This section defines the property set restrictions for the method
types that are applicable to the "VPOLL" calendar component. Each
method is defined using a table that clarifies the property
constraints that define the particular method.
The presence column uses the following values to assert whether a
property is required or optional, and the number of times it may
appear in the iCalendar object.
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+-----------------+-------------------------------------------------+
| Presence Value | Description |
+-----------------+-------------------------------------------------+
| 1 | One instance MUST be present. |
| 1+ | At least one instance MUST be present. |
| 0 | Instances of this property MUST NOT be present. |
| 0+ | Multiple instances MAY be present. |
| 0 or 1 | Up to 1 instance of this property MAY be |
| | present. |
+-----------------+-------------------------------------------------+
The following summarizes the methods that are defined for the "VPOLL"
calendar component.
+------------+------------------------------------------------------+
| Method | Description |
+------------+------------------------------------------------------+
| PUBLISH | Post notification of an poll. Used primarily as a |
| | method of advertising the existence of a poll. |
| | |
| REQUEST | To make a request for a poll. This is an explicit |
| | invitation to one or more voters. Poll requests are |
| | also used to update, change or confirm an existing |
| | poll. Clients that cannot handle REQUEST MAY degrade |
| | the poll to view it as a PUBLISH. REQUEST SHOULD NOT |
| | be used just to set the status of the poll - |
| | POLLSTATUS provides a more compact approach. |
| | |
| REPLY | Reply to a poll request. Voters may set the RESPONSE |
| | properties to supply the current vote in the range 0 |
| | to 100. |
| | |
| CANCEL | Cancel a poll. |
| | |
| REFRESH | A request is sent to an Organizer by a Voter asking |
| | for the latest version of a poll to be resent to the |
| | requester. |
| | |
| POLLSTATUS | Used to send the current state of the poll to all |
| | voters. The VPOLL can contain a reduced set of |
| | properties but MUST contain DTSTAMP, SEQUENCE (if |
| | not 0), UID, ORGANIZER properties and VVOTER |
| | components. |
| | |
+------------+------------------------------------------------------+
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The "REQUEST" method in a "VPOLL" component provides the following
scheduling functions:
o Invite "Voters" to respond to the poll.
o Change the items being voted upon.
o Complete or confirm the poll.
o Response to a "REFRESH" request.
o Update the details of an existing vpoll.
o Update the status of "Voters".
o Forward a "VPOLL" to another uninvited CU.
o For an existing "VPOLL" calendar component, delegate the role of
"Voter" to another CU.
o For an existing "VPOLL" calendar component, change the role of
"Organizer" to another CU.
The "Organizer" originates the "REQUEST". The recipients of the
"REQUEST" method are the CUs voting in the poll, the "Voters".
"Voters" use the "REPLY" method to convey votes to the "Organizer".
The "UID" and "SEQUENCE" properties are used to distinguish the
various uses of the "REQUEST" method. If the "UID" property value in
the "REQUEST" is not found on the recipient's calendar, then the
"REQUEST" is for a new "VPOLL" calendar component. If the "UID"
property value is found on the recipient's calendar, then the
"REQUEST" is for an update, or a reconfirmation of the "VPOLL"
calendar component.
For the "REQUEST" method only a single iCalendar object is permitted.
This method type is an iCalendar object that conforms to the
following property constraints:
+----------------------------------------------+
| Constraints for a METHOD:REQUEST of a VPOLL |
+----------------------------------------------+
+----------------------------------------------+
+--------------------+----------+-----------------------------------+
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| | | |
| VTIMEZONE | 0+ | MUST be present if any date/time |
| | | refers to a timezone. |
| | | |
| IANA-COMPONENT | 0+ | |
| X-COMPONENT | 0+ | |
| | | |
| VEVENT | 0+ | Depending upon the poll mode in |
| | | effect there MAY be candidate |
| | | components included in the poll |
| | | component. |
| | | |
| VFREEBUSY | 0 | |
| | | |
| VJOURNAL | 0+ | Depending upon the poll mode in |
| | | effect there MAY be candidate |
| | | components included in the poll |
| | | component. |
| | | |
| VTODO | 0+ | Depending upon the poll mode in |
| | | effect there MAY be candidate |
| | | components included in the poll |
| | | component. |
+--------------------+----------+-----------------------------------+
6.3.1.2.1. Rescheduling a poll
The "REQUEST" method may be used to reschedule a poll, that is force
a revote. A rescheduled poll involves a change to the existing poll
in terms of its time the components being voted on may have changed.
If the recipient CUA of a "REQUEST" method finds that the "UID"
property value already exists on the calendar but that the "SEQUENCE"
(or "DTSTAMP") property value in the "REQUEST" method is greater than
the value for the existing poll, then the "REQUEST" method describes
a rescheduling of the poll.
6.3.1.2.2. Updating or Reconfirmation of a Poll
The "REQUEST" method may be used to update or reconfirm a poll. An
update to an existing poll does not involve changes to the time or
candidates, and might not involve a change to the location or
description for the poll. If the recipient CUA of a "REQUEST" method
finds that the "UID" property value already exists on the calendar
and that the "SEQUENCE" property value in the "REQUEST" is the same
as the value for the existing poll, then the "REQUEST" method
describes an update of the poll details, but not a rescheduling of
the POLL.
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The update "REQUEST" method is the appropriate response to a
"REFRESH" method sent from a "Voter" to the "Organizer" of a poll.
The "Organizer" of a poll may also send unsolicited "REQUEST"
methods. The unsolicited "REQUEST" methods may be used to update the
details of the poll without rescheduling it, to update the "RESPONSE"
property values, or to reconfirm the poll.
6.3.1.2.3. Confirmation of a Poll
The "REQUEST" method may be used to confirm a poll, that is announce
the winner in BASIC mode. The STATUS MUST be set to CONFIRMED and
for BASIC mode a VPOLL POLL-WINNER property must be provided with the
poll-id of the winning component.
6.3.1.2.4. Closing a Poll
The "REQUEST" method may be used to close a poll, that is indicate
voting is completed. The STATUS MUST be set to COMPLETED.
6.3.1.2.5. Delegating a POll to Another CU
Some calendar and scheduling systems allow "Voters" to delegate the
vote to another "Calendar User". iTIP supports this concept using the
following workflow. Any "Voter" may delegate their right to vote in
a poll to another CU. The implication is that the delegate
participates in lieu of the original "Voter", NOT in addition to the
"Voter". The delegator MUST notify the "Organizer" of this action
using the steps outlined below. Implementations may support or
restrict delegation as they see fit. For instance, some
implementations may restrict a delegate from delegating a "REQUEST"
to another CU.
The "Delegator" of a poll forwards the existing "REQUEST" to the
"Delegate". The "REQUEST" method MUST include a "Voter" property
with the calendar address of the "Delegate". The "Delegator" MUST
also send a "REPLY" method to the "Organizer" with the "Delegator's"
"Voter" property "DELEGATED-TO" parameter set to the calendar address
of the "Delegate". Also, a new "Voter" property for the "Delegate"
MUST be included and must specify the calendar user address set in
the "DELEGATED-TO" parameter, as above.
In response to the request, the "Delegate" MUST send a "REPLY" method
to the "Organizer", and optionally to the "Delegator". The "REPLY"
method SHOULD include the "Voter" property with the "DELEGATED-FROM"
parameter value of the "Delegator's" calendar address.
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The "Delegator" may continue to receive updates to the poll even
though they will not be attending. This is accomplished by the
"Delegator" setting their "role" attribute to "NON-PARTICIPANT" in
the "REPLY" to the "Organizer".
6.3.1.2.6. Changing the Organizer
The situation may arise where the "Organizer" of a "VPOLL" is no
longer able to perform the "Organizer" role and abdicates without
passing on the "Organizer" role to someone else. When this occurs,
the "Voters" of the "VPOLL" may use out-of-band mechanisms to
communicate the situation and agree upon a new "Organizer". The new
"Organizer" should then send out a new "REQUEST" with a modified
version of the "VPOLL" in which the "SEQUENCE" number has been
incremented and the "ORGANIZER" property has been changed to the new
"Organizer".
6.3.1.2.7. Sending on Behalf of the Organizer
There are a number of scenarios that support the need for a "Calendar
User" to act on behalf of the "Organizer" without explicit role
changing. This might be the case if the CU designated as "Organizer"
is sick or unable to perform duties associated with that function.
In these cases, iTIP supports the notion of one CU acting on behalf
of another. Using the "SENT-BY" parameter, a "Calendar User" could
send an updated "VPOLL" "REQUEST". In the case where one CU sends on
behalf of another CU, the "Voter" responses are still directed back
towards the CU designated as "Organizer".
6.3.1.2.8. Forwarding to an Uninvited CU
A "Voter" invited to a "VPOLL" calendar component may send the
"VPOLL" calendar component to another new CU not previously
associated with the "VPOLL" calendar component. The current "Voter"
participating in the "VPOLL" calendar component does this by
forwarding the original "REQUEST" method to the new CU. The new CU
can send a "REPLY" to the "Organizer" of the "VPOLL" calendar
component. The reply contains a "Voter" property for the new CU.
The "Organizer" ultimately decides whether or not the new CU becomes
part of the poll and is not obligated to do anything with a "REPLY"
from a new (uninvited) CU. If the "Organizer" does not want the new
CU to be part of the poll, the new "Voter" property is not added to
the "VPOLL" calendar component. The "Organizer" MAY send the CU a
"CANCEL" message to indicate that they will not be added to the poll.
If the "Organizer" decides to add the new CU, the new "Voter"
property is added to the "VPOLL" calendar component. Furthermore,
the "Organizer" is free to change any "Voter" property parameter from
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the values supplied by the new CU to something the "Organizer"
considers appropriate. The "Organizer" SHOULD send the new CU a
"REQUEST" message to inform them that they have been added.
When forwarding a "REQUEST" to another CU, the forwarding "Voter"
MUST NOT make changes to the original message.
6.3.1.2.9. Updating Voter Status
The "Organizer" of an poll may also request updated status from one
or more "Voters". The "Organizer" sends a "REQUEST" method to the
"Voter" and sets the "VOTER;RSVP=TRUE" property parameter. The
"SEQUENCE" property for the poll is not changed from its previous
value. A recipient will determine that the only change in the
"REQUEST" is that their "RSVP" property parameter indicates a request
for updated status. The recipient SHOULD respond with a "REPLY"
method indicating their current vote with respect to the "REQUEST".
6.3.1.3. REPLY
The "REPLY" method in a "VPOLL" calendar component is used to respond
(e.g., accept or decline) to a "REQUEST" or to reply to a delegation
"REQUEST". When used to provide a delegation response, the
"Delegator" SHOULD include the calendar address of the "Delegate" on
the "DELEGATED-TO" property parameter of the "Delegator's" "Voter"
property. The "Delegate" SHOULD include the calendar address of the
"Delegator" on the "DELEGATED-FROM" property parameter of the
"Delegate's" "Voter" property.
The "REPLY" method is also used when processing of a "REQUEST" fails.
Depending on the value of the "REQUEST-STATUS" property, no action
may have been performed.
The "Organizer" of a poll may receive the "REPLY" method from a CU
not in the original "REQUEST". For example, a "REPLY" may be
received from a "Delegate" to a poll. In addition, the "REPLY"
method may be received from an unknown CU (a "Party Crasher"). This
uninvited "Voter" may be accepted, or the "Organizer" may cancel the
poll for the uninvited "Voter" by sending a "CANCEL" method to the
uninvited "Voter".
A "Voter" MAY include a message to the "Organizer" using the
"COMMENT" property. For example, if the user indicates a low
interest and wants to let the "Organizer" know why, the reason can be
expressed in the "COMMENT" property value.
The "Organizer" may also receive a "REPLY" from one CU on behalf of
another. Like the scenario enumerated above for the "Organizer",
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| X-COMPONENT | 0+ | |
+--------------------+----------+-----------------------------------+
7. CalDAV Extensions
This specification extends [RFC4791] in that it defines a new
component and new iCalendar properties to be supported and requires
extra definitions related to time-ranges and reports.
Additionally, it extends [RFC6638] as a VPOLL component is a
schedulable entity.
7.1. Calendar Collection Properties
This section defines new CalDAV properties for calendar collections.
7.1.1. CALDAV:supported-vpoll-component-sets
Name: supported-vpoll-component-sets
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Specifies the calendar component types (e.g., VEVENT,
VTODO, etc.) and combination of types that may be included in a
VPOLL component.
Conformance: This property MAY be defined on any calendar
collection. If defined, it MUST be protected and SHOULD NOT be
returned by a PROPFIND DAV:allprop request (as defined in
Section 12.14.1 of [RFC4918]).
Description: The CALDAV:supported-vpoll-component-sets property is
used to specify restrictions on the calendar component types that
VPOLL components may contain in a calendar collection.
It also specifies the combination of allowed component types.
Any attempt by the client to store VPOLL components with component
types or combinations of types not listed in this property, if it
exists, MUST result in an error, with the CALDAV:supported-vpoll-
component-sets precondition defined in Section 7.2 being violated.
Since this property is protected, it cannot be changed by clients
using a PROPPATCH request. However, clients can initialize the
value of this property when creating a new calendar collection
with extended MKCOL or MKCALENDAR. In the absence of this
property, the server MUST accept all component types, and the
client can assume that all component types are accepted.
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Individual members of a group of choices all count towards the
total, that is, a group does NOT count as a single item.
Conformance: This property MAY be defined on any calendar
collection. If defined, it MUST be protected and SHOULD NOT be
returned by a PROPFIND DAV:allprop request (as defined in
Section 12.14.1 of [RFC4918]).
Description: The CALDAV:vpoll-max-items is used to specify a numeric
value that indicates the maximum number of iCalendar components in
any one instance of a VPOLL calendar object resource stored in a
calendar collection. Any attempt to store a calendar object
resource with more components per instance than this value MUST
result in an error, with the CALDAV: vpoll-max-items precondition
Section 7.2 being violated. In the absence of this property, the
client can assume that the server can handle any number of items
in a VPOLL calendar component.
Definition:
<!ELEMENT vpoll-max-items (#PCDATA)>
PCDATA value: a numeric value (integer greater than zero)
Example:
<C:vpoll-max-items
xmlns:C="urn:ietf:params:xml:ns:caldav"
>25</C:vpoll-max-items>
7.1.3. CALDAV:vpoll-max-active
Name: vpoll-max-active
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Provides a numeric value indicating the maximum number of
active vpolls at any one time.
Conformance: This property MAY be defined on any calendar
collection. If defined, it MUST be protected and SHOULD NOT be
returned by a PROPFIND DAV:allprop request (as defined in
Section 12.14.1 of [RFC4918]).
Description: The CALDAV:vpoll-max-active is used to specify a
numeric value that indicates the maximum number of active VPOLLs
at any one time. Any attempt to store a new active VPOLL calendar
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object resource which results in exceeding this limit MUST result
in an error, with the CALDAV: vpoll-max-active precondition
Section 7.2 being violated. In the absence of this property, the
client can assume that the server can handle any number of active
VPOLLs.
Definition:
<!ELEMENT vpoll-max-active (#PCDATA)>
PCDATA value: a numeric value (integer greater than zero)
Example:
<C:vpoll-max-active
xmlns:C="urn:ietf:params:xml:ns:caldav"
>25</C:vpoll-max-active>
7.1.4. CALDAV:vpoll-max-voters
Name: vpoll-max-voters
Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Provides a numeric value indicating the maximum number of
voters for any instance of a VPOLL calendar object resource stored
in the calendar collection.
Conformance: This property MAY be defined on any calendar
collection. If defined, it MUST be protected and SHOULD NOT be
returned by a PROPFIND DAV:allprop request (as defined in
Section 12.14.1 of [RFC4918]).
Description: The CALDAV:vpoll-max-voters is used to specify a
numeric value that indicates the maximum number of VOTER
properties for any one instance of a VPOLL calendar object
resource stored in a calendar collection. Any attempt to store a
calendar object resource with more VOTER properties per instance
than this value MUST result in an error, with the CALDAV: vpoll-
max-voters precondition Section 7.2 being violated. In the
absence of this property, the client can assume that the server
can handle any number of voters in a VPOLL calendar component.
Definition:
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<!ELEMENT vpoll-max-voters (#PCDATA)>
PCDATA value: a numeric value (integer greater than zero)
Example:
<C:vpoll-max-voters
xmlns:C="urn:ietf:params:xml:ns:caldav"
>25</C:vpoll-max-voters>
7.1.5. CalDAV:even-more-properties
1. vpoll-supported-mode poll options - e.g "vpoll-basic"
7.1.6. Extensions to CalDAV scheduling
This specification extends [RFC6638].
Each section of Appendix A "Scheduling Privileges Summary" is
extended to include VPOLL.
Any reference to the ATTENDEE property should be read to include the
VOTER property. That is, for scheduling purposes the VOTER property
is handled in exactly the same manner as the ATTENDEE property.
7.2. Additional Preconditions for PUT, COPY, and MOVE
This specification creates additional Preconditions for PUT, COPY,
and MOVE methods. These preconditions apply when a PUT operation of
a VPOLL calendar object resource into a calendar collection occurs,
or when a COPY or MOVE operation of a calendar object resource into a
calendar collection occurs, or when a COPY or MOVE operation occurs
on a calendar collection.
The new preconditions are:
(CALDAV:supported-vpoll-component-sets): The VPOLL resource
submitted in the PUT request, or targeted by a COPY or MOVE
request, MUST contain a type or combination of calendar component
that is supported in the targeted calendar collection;
(CALDAV:vpoll-max-items): The VPOLL resource submitted in the PUT
request, or targeted by a COPY or MOVE request, MUST have a number
of sub-components (excluding VTIMEZONE) less than or equal to the
value of the CALDAV:vpoll-max-items property value Section 7.1.2
on the calendar collection where the resource will be stored;
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(CALDAV:vpoll-max-active): The PUT request, or COPY or MOVE request,
MUST not result in the number of active VPOLLs being greater than
the value of the CALDAV:vpoll-max-active property value
Section 7.1.3 on the calendar collection where the resource will
be stored;
(CALDAV:vpoll-max-voters): The VPOLL resource submitted in the PUT
request, or targeted by a COPY or MOVE request, MUST have a number
of VOTER properties less than or equal to the value of the
CALDAV:vpoll-max-voters property value Section 7.1.4 on the
calendar collection where the resource will be stored;
7.3. CalDAV:calendar-query Report
This allows the retrieval of VPOLLs and their included components.
The query specification allows queries to be directed at the
contained sub-components. For VPOLL queries this feature is
disallowed. Time-range queries can only target the vpoll component
itself.
7.3.1. Example: Partial Retrieval of VPOLL
In this example, the client requests the server to return specific
components and properties of the VPOLL components that overlap the
time range from December 4, 2012, at 00:00:00 A.M. UTC to December
5, 2012, at 00:00:00 A.M. UTC. In addition, the DAV:getetag
property is also requested and returned as part of the response.
Note that due to the CALDAV: calendar-data element restrictions, the
DTSTAMP property in VPOLL components has not been returned, and the
only property returned in the VCALENDAR object is VERSION.
>> Request <<
REPORT /cyrus/work/ HTTP/1.1
Host: cal.example.com
Depth: 1
Content-Type: application/xml; charset="utf-8"
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<C:calendar-query xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav">
<D:prop>
<D:getetag/>
<C:calendar-data>
<C:comp name="VCALENDAR">
<C:prop name="VERSION"/>
<C:comp name="VPOLL">
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<D:response>
<D:href>http://cal.example.com/cyrus/work/poll3.ics</D:href>
<D:propstat>
<D:prop>
<D:getetag>"fffff-abcd3"</D:getetag>
<C:calendar-data>BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
BEGIN:VPOLL
DTSTART;TZID=US/Eastern:20121204T100000
DURATION:PT4D
SUMMARY:Poll #3
UID:DC6C50A017428C5216A2F1CD@example.com
END:VPOLL
END:VCALENDAR
</C:calendar-data>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
7.4. CalDAV time rangesSection 9.9 "CALDAV:time-range XML Element" in [RFC4791] describes
how to specify time ranges to limit the set of calendar components
returned by the server. This specification extends [RFC4791] to
describe the meaning of time ranges for VPOLL
A VPOLL component is said to overlap a given time range if the
condition for the corresponding component state specified in the
table below is satisfied. The conditions depend on the presence of
the DTSTART, DURATION, DTEND, COMPLETED and CREATED properties in the
VPOLL component. Note that, as specified above, the DTEND value MUST
be a DATE-TIME value equal to or after the DTSTART value if
specified.
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[RFC5545] Desruisseaux, B., "Internet Calendaring and Scheduling
Core Object Specification (iCalendar)", RFC 5545,
September 2009.
[RFC5546] Daboo, C., "iCalendar Transport-Independent
Interoperability Protocol (iTIP)", RFC 5546, December
2009.
[RFC6047] Melnikov, A., "iCalendar Message-Based Interoperability
Protocol (iMIP)", RFC 6047, December 2010.
[RFC6638] Daboo, C. and B. Desruisseaux, "Scheduling Extensions to
CalDAV", RFC 6638, June 2012.
[W3C.REC-xml-20060816]
Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and
F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fourth
Edition)", World Wide Web Consortium Recommendation REC-
xml-20060816, August 2006,
<http://www.w3.org/TR/2006/REC-xml-20060816>.
Appendix A. Open issues
Notifications: Need to do a section on what Notifications to
support.
A. VPOLL is about to end and you haven't voted on it yet.
Instead reuse VALARMS to notify the user?
Future: Restarting a confirmed/completed VPOLL What to do with
changes to STATUS:CONFIRMED? Allow them or not? What do to that
poll had a winning event or todo.
Stress VPOLL UID MUST be unique
Changing status back from CONFIRMED MUST adjust status of any
events booked as a result of confirmation.
MUST winning event be cancelled for POLL-MODE basic? No - VOTER
has indicated now unable to attend - want to revote
Future: Voting on a confirmed/completed VPOLL Can a VOTER vote after
completion? May be unable to attend and wants to indicate.
Requires retention of VPOLL
retention period
Removed status
ORGANIZER/ATTENDEE validity Can a user create a poll with scheduled
events where that user's isn't the organizer of the poll? So is
there a requirement that the account that poll is on is able to
create each one of the resources in the poll? i.e. I can't create
a poll with a set of events where I am just the attendee of the
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